The present invention relates to laser work stations and, more specifically, to a laser work station in which a workpiece guidance system may be calibrated to reflect the actual position of the workpiece therein.
Laser work stations are now widely employed for cutting and welding various types of parts. Generally, in the processing of sheet metal workpieces, the workpiece may be supported upon a work table and moved by a clamping and guidance system about the table relative to a laser head at a fixed work station, or the laser head may be moved relative to the workpiece by the guidance system. In the latter type of laser work station, it is desirable to be able to effect relative movement of the laser head in X, Y, and Z axes.
In some work stations, the workpieces are loaded onto the workpiece support or work table automatically by robots or other loading devices, and in others the workpieces are loaded manually. Some work tables have loaders cooperating therewith to position the workpiece thereon in a position to be engaged by the clamping assembly for movement by the guidance system.
In some machining centers, workpieces are initially processed and moved from a first machine tool such as a punching or nibbling machine, and the further processing of the workpiece may require the precise alignment of the workpiece in the guidance system of the laser work station. In some installations, the workpiece may be supported on a cart or carrier which is moved into the work station, which may be moved within the work station, and which then may be withdrawn therefrom so as to minimize the handling within the station. In other installations, the workpiece may be moved into the work station on a pallet.
In the copending application of Fredrich Kilian and Hans Klingel, Ser. No. 07/577,475 filed Sep. 4, 1990, there is disclosed a laser work station in which the workpiece is moved on a carriage into the work station, and a sensor probe is provided for movement within reference formations in the workpiece to provide information on their precise location within the work station for correction of the X-Y guidance system to the coordinates of the workpiece on the support. However, such mechanical probes have been found to have limited accuracy and to be limited in the types of formations which they may detect.
It is an object of the present invention to provide a ,novel laser work station in which an optical sensor system accurately senses the position of reference formations on the workpiece to enable precise calibration of the guidance system to the actual position of the workpiece within the station.
It is also an object to provide such a laser work station in which the workpieces may be partially processed prior to entry thereinto, and their position within the station may be precisely and quickly determined for calibration of the guidance system.
Another object is to provide such a laser work station in which the X-Y guidance system of a laser work station is rapidly and accurately compensated to permit precise operation on a workpiece which has been previously processed and/or which has shifted as it is moved within the work station.